I’ve been blogging a lot recently about dangerous viruses, like the flu and norovirus. But, truth be told, a lot of viruses we harbor don’t make us sick. They may even make us healthy. You’d think they’d be worth getting to know. But they’re mostly a mystery to us.

The collection of viruses that are dwelling inside you right now is known collectively as the virome. You might think these viruses were the sort that infect your cells. Some indeed are. There’s a good chance you harbor papillomaviruses in some of your skin cells, for example. And chances are they won’t cause you any harm. Rather than blasting apart your cells, papillomaviruses merely accelerate the rate at which your cells divide. Since you slough off your skin cells, you’re rid of the viruses soon enough anyway. No harm, no foul. The only trouble these viruses can cause is when they end up accelerating your cells until they spin out of control. They can cause cervical cancer and warts when this happens.

And yet your own cells are not the only targets for viruses. The bacteria, fungi, and other residents of your body can serve as hosts as well. Indeed, of the several million viruses in you right now, most probably infect bacteria. As Sarah Williams writes in the Proceedings of the National Academy of Sciences (open access), virologists who have charted the huge diversity of viruses in the outside world are now going inside. There’s not that much difference between us and a coral reef when you look at us as an ecosystem.

The virus survey is in its very early stages, partly because it’s trickier to identify viruses than bacteria. At this stage of the virome saga, most of the viruses that researchers dredge out of our bodies are entirely new to science. Each of us has a unique virome as well, with a unique balance of species that can change quickly. But someday they may understand the virome well enough to manipulate it for our well being. Some scientists suspect that viruses may influence our health in many ways, some obvious and some subtle. As Williams notes, a person’s virome could influence how severe unrelated diseases might be, such as asthma and cystic fibrosis.

Over at Environmental Health Perspectives, Carol Portera takes a look at another way we might harness the virome: to kill bad bacteria (also open access). The idea of using viruses to cure infectious diseases is about a century old now, but the method–known as phage therapy–has never managed to go mainstream in the West. That’s just starting to change. The FDA has approved viruses to kill infectious bacteria on food, for example. Research is fairly far along in using viruses to disinfect wounds, cure acne, and clean water supplies. If you’re worried about putting viruses in your body, relax–there are swarms of bacteria-infecting viruses in many foods you eat, such as yogurt.

Someday, once we get to know our virome much better, a new generation of scientists may study our bodies as ecologists today study lions on the savanna. Predators play a huge role in food webs, influencing the populations of a vast number of species (I wrote about this in detail in Scientific American last year). Viruses probably play a similar role in our bodies, influencing who wins and who loses in the fierce competition among thousands of species for survival inside us. Ecologists are exploring how to restore dysfunctional ecosystems by returning their predators. Perhaps we may manage our inner lions in the future.

For more information on viruses, see my book, A Planet of Viruses. And, in closing…here’s a cool video of a virus invading a bacteria. It’s really a virus, not a lunar lander.

There are 8 Comments. Add Yours.

Mike Lewinski
February 8, 2013

There’s a quote I love from “Lives of a Cell” by Lewis Thomas that this reminds me of:

“Some bacteria are only harmful to us when they make exotoxins, and they only do this when they are, in a sense, diseased themselves. The toxins of diphtheria bacilli and streptococci are produced when the organisms have been infected by a bacteriophage; it is the virus that provides the code for toxin. Uninfected bacteria are uninformed. When we catch diphtheria it is a virus infection, but not of us. Our involvement is not that of an adversary in a straightforward game, but more like blundering into someone else’s accident. I can think of a few microorganisms, possibly the tubercle bacillus, the syphilis spirochete, the malarial parasite, and a few others, that have a selective advantage in their ability to infect human beings, but there is nothing to be gained, in an evolutionary sense, by the capacity to cause illness or death. Pathogenicity may be something of a disadvantage for most microbes, carrying lethal risks more frightening to them than to us. The man who catches a meningococcus is in considerably less danger for his life, even without chemotherapy, than meningococci with the bad luck to catch a man. Most meningococci have the sense to stay out on the surface, in the rhinopharynx. During epidemics this is where they are to be found in the majority of the host population, and it generally goes well. It is only in the unaccountable minority, the “cases,” that the line is crossed, and then there is the devil to pay on both sides, but most of all for the meningococci.”

Ed Rybicki
February 9, 2013

Great article – as usual…B-) As a practicing virologist, it is endlessly fascinating to me just how MANY viruses are associated with us – and with our commensals and parasites. And now, thanks to next-gen sequencing, we can start to determine just which, and what they infect, and how they interact.

And as for “It’s really a virus, not a lunar lander”: I have used pictures of the Apollo Project LEM juxtaposed with a T-even phage for many years now, as an illustration of how form follows function. Namely, protecting nucleic acid and delivering it to another environment. I doubt the engineers had any idea they were recreating a phage, though!http://www.mcb.uct.ac.za/tutorial/virions_are_virus_particles.htm

Emilie Andreoulis
February 15, 2013

According to ” the message given by the extraterrestrials ” to Raël, we were created by Intelligent and Loving people…so Their Creation is in balance and perfect. Scientists discover it nowadays…

Nice one. Thanks for awakening my interest in science. I am a layman reader but I am quite fascinated.

LC
February 25, 2013

so, can I go get next to a friend who has strep and maybe it’ll go in and kill this sinusitis bacteria I’ve been plagued with for months..? I’m almost tempted to try!!

Nathan
February 28, 2013

I’m just putting a thought out there. What if the bacteria is what makes us get older or age ? I’m thinking if there increasing our cells within the volum or atoms does that mean where getting older through them if we remove them or with the harm of other bacteria what will happen too us? I know it’s impossible too stop aging but the cells in our body’s are rapidly recalling which if we got like say an banana in 4-6 days it will go bad by putting it in a freezer it will survive 4 – 14 weeks because of the freeze since Bactria can’t live in cold the age producing is slowed down or there making a cellure structure like nano machines too help the body but what if we make cryogenic freeze that same bacteria can’t live in freeze so the body’s of us well be like this for how long we live in that ice cube .

Nathan
February 28, 2013

This is only a theory. What if we remove this Bacteria that is changing are cellure structer will we stop aging? As it says ( Rather than blasting apart your cells, papillomaviruses merely accelerate the rate ) which means we are aging through bacteria I could be wrong but it is a theory like so if we use a subject if we cryogenic a banana it will survive in there for 4 – 30 weeks because bacteria is reduced of that of a freeze there for bacteria can’t live in a cold place so it takes sooo long to to turn into nonliving biotic fruit or anything else like anboitic why can rocks be there but living things why do trees take 200 years why does dirt stay healthy for other thing like for food. But I’m just might be over the top if we remove this bacteria and stop them from making our cellure expanding or multiplying do we stop aging? Bacteria live because life is on its like the biotic vs the anboitic or decomposer biotics that circle of life but what happens if we remove the 1 of the 4 stages of live could we live for infinity or die by hunger/war/population/dehydration. But Ether way what will happen if we remove the stuff that multiples our cells or accelerate?

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